Physics – Class 12 Mock Test 4

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Question 1 of 10

1. A long solenoid has 500 turns per cm and carries a current I. The magnetic field at its center is 7.54 × 10^-2 Wb m^-2. Another long solenoid has 300 turns per cm and it carries a current \(\frac {I}{3}\). What is the value of magnetic field at the center?

1.50 × 10^-2 Wb/m²

1.05 × 10^-3 Wb/m²

1.50 × 10^-3 Wb/m²

1.50 × 10^-5 Wb/m²

Question 1 of 10

Question 2 of 10

2. Calculate the speed of an electron if it travels in a circular path of radius 50 cm in a magnetic field of 5 × 10^-3 T.

4 × 10⁷ m/s

44 × 10⁷ m/s

0.4 × 10⁷ m/s

440 × 10⁷ m/s

Question 2 of 10

Question 3 of 10

3. Find the false statement.

Wheatstone bridge is analogous to simple level system

Wheatstone bridge is susceptible to high dc current

A galvanometer with low resistance in series is an ammeter

Wheatstone bridge cannot be used forprecision measurement because of the error introduced in contact resistance

Question 3 of 10

Question 4 of 10

4. Two parallel, long wires carry currents I₁ and I₂ where I₁ > I₂. When the currents are in the same direction, the magnetic field at a point midway between the wires is 50 μT. If the direction of I₂ is revered, the field becomes 100 μT. What is the value of \(\frac {I_1}{I_2}\)?

Question 4 of 10

Question 5 of 10

5. The north pole of a magnet is brought near a stationary negatively charged conductor. What is the force experienced by it at the poles?

Depend on the nature of the conductor

Maximum

Zero

Minimum

Question 5 of 10

Question 6 of 10

6. If an electron entering at a magnetic field of 2 × 10^-2 T has a velocity of 3 × 10⁷ ms^-1 and describes a circle of radius 8 × 10^-3 m, then find the value of \(\frac {e}{m}\) of the electron.

1.567 × 10¹¹ C/Kg

1.875 × 10¹¹ C/Kg

18 × 10¹¹ C/Kg

190 × 10¹¹ C/Kg

Question 6 of 10

Question 7 of 10

7. An electron moving with a velocity of 15 ms^-1 enters a uniform magnetic field of 0.2 T, along a direction parallel to the field. What would be its trajectory in this field?

Helical

Circular

Straight path

Elliptical

Question 7 of 10

Question 8 of 10

8. Alpha particles of mass 6.68 × 10^-27 Kg and charge 3.2 × 10^-19 C is accelerated in a cyclotron in which a magnetic field of 1.25 T is applied perpendicular to the dees. How rapidly should the electric field between the dees be reversed?

955.25 × 10^-8 s

55.25 × 10^-8 s

575.25 × 10^-8 s

5.25 × 10^-8 s

Question 8 of 10

Question 9 of 10

9. A cell has an emf of 6V, internal resistance of 1 ohms and a current of 0.5 A passing through it. This cell is connected to a resistor. Find out the resistance of the resistor.

10 ohms

13 ohms

11 ohms

12 ohms

Question 9 of 10

Question 10 of 10

10. What is the space around a current-carrying conductor, in which its magnetic effect can be experienced called?

Electric field

Magnetic field

Charge distribution

Magnetic pole

Question 10 of 10